I. Field of the Invention
The present invention relates generally to systems and methods for performing minimally invasive cardiac medical procedures. More particularly, the present invention is directed to systems and methods for creating space within the chest cavity to more easily perform minimally invasive cardiac procedures.
II. Discussion of the Prior Art
Minimally invasive cardiac procedures (otherwise known as xe2x80x9cendoscopicxe2x80x9d or xe2x80x9cclosed chestxe2x80x9d cardiac procedures) are gaining favor in the medical community for a variety of well-founded reasons. A primary reason for the increasing popularity of such minimally invasive procedures is the significant reduction in trauma to the patient relative to traditional xe2x80x9copen chestxe2x80x9d procedures, which require a sternotomy to gain access to the heart. The reduction in trauma to the patient translates into shortened periods of hospitalization, which consequently reduces the overall cost associated with such minimally invasive cardiac procedures.
An area of heightened interest is minimally invasive bypass surgery, such as coronary artery bypass graft (CABG) surgery. CABG surgery involves connecting a source of arterial blood downstream from a narrow or occluded section of a coronary artery for the purpose of providing an improved supply of oxygenated blood to the vasculature of the heart. CABG surgery may be performed on a stopped heart or a beating heart. During stopped heart CABG surgery, a full cardiopulmonary bypass (CPB) circuit is employed to divert blood from the lungs for artificial oxygenation at a remote location. This may be referred to as providing xe2x80x9cfullxe2x80x9d cardiac support. During beating heart CABG surgery, it is necessary to provide supplemental circulatory support in order to maintain the hemodynamic stability of the patient. This is preferably accomplished by providing right-heart and/or left-heart assistance, wherein blood is rerouted from one location in the heart to another under the direction of a blood pump so as to obviate the need for an artificial oxygenator, filter, tubing, saline, etc. associated with stopped heart CABG surgery. This may be referred to as providing xe2x80x9cpartialxe2x80x9d cardiac support.
A significant challenge in performing minimally invasive cardiac procedures, such as stopped heart or beating heart CABG surgery, is the lack of space within the chest cavity. More specifically, the chest cavity is constrained in terms of the space available for the surgeon to operate within. This space constraint makes it difficult to manipulate and position the endoscopic instruments, as well as to establish adequate visualization within the chest cavity. The space constraint within the chest cavity thus makes it increasingly challenging for the physician to perform the necessary steps in the given cardiac procedure.
The present invention is directed at eliminating, or at least minimizing the effects of, the above-identified problems.
The present invention incorporates a multitude of embodiments which enable the introduction of insufflation fluid (gas or liquid) into the chest cavity for the purposes of creating additional space within the chest cavity to facilitate the performance of any of a variety of minimally invasive cardiac medical procedures. In one embodiment, the insufflation system is an access port incorporating a separate insufflation port through which insufflation fluids may be introduced to pressurize the chest cavity while the access port is employed to introduce instruments for performing the minimally invasive cardiac procedure. In a second embodiment, the access port has an elongated body capable of being introduced into an organ disposed within the chest cavity (including but not limited to the heart and associated vasculature), wherein the body includes a separate insufflation port through which insufflation fluid may be introduced into the chest cavity. Contemplated within this embodiment is a variation wherein the body of the access port can be made of a synthetic graft material (with or without an insufflation lumen) capable of being sealed and severed near the proximal region (following use) and subsequently pushed into the chest cavity (leaving the distal region sealed within the organ) for later removal and use should repeat procedures require accessing the internal organ. A third main insufflation device according to the present invention involves equipping a minimally invasive coaxial cannula assembly with a separate insufflation port for introducing insufflation fluid into the chest cavity while the cannula assembly is used within the heart to augment or replace the heart""s own beating function. This feature of augmenting or replacing the heart""s own beating function during the insufflation of the chest cavity is a significant aspect of the present invention in that it provides the ability to counteract or overcome the heart""s diminished pumping ability (particularly on the thin-walled right side of the heart) due to any collapse of the heart chambers or associated vasculature which stems from insufflating the chest cavity. In this regard, a peripheral access coaxial cannula assembly may be similarly employed to augment or replace the heart""s own beating function. In both cases, the cardiac output of the heart is maintained. In the context of right heart support during beating heart surgery, both coaxial cannulation systems also serve to reroute blood past the right ventricle. This rerouting past the right ventricle effectively empties the right ventricle, providing yet another space creating mechanism within the chest cavity.